diff --git a/kcmkwin/kwindecoration/kcm.cpp b/kcmkwin/kwindecoration/kcm.cpp
index 95087925c..5d4ca7cb8 100644
--- a/kcmkwin/kwindecoration/kcm.cpp
+++ b/kcmkwin/kwindecoration/kcm.cpp
@@ -242,11 +242,6 @@ bool KCMKWinDecoration::isSaveNeeded() const
     return !m_settings->borderSizeAuto() && borderSizeIndexFromString(m_settings->borderSize()) != m_borderSizeIndex;
 }
 
-bool KCMKWinDecoration::isDefaults() const
-{
-    return m_settings->borderSizeAuto() && recommendedBorderSize() == m_borderSizeIndex;
-}
-
 int KCMKWinDecoration::borderSizeIndexFromString(const QString &size) const
 {
     return Utils::getBorderSizeNames().keys().indexOf(Utils::stringToBorderSize(size));
diff --git a/kcmkwin/kwindecoration/kcm.h b/kcmkwin/kwindecoration/kcm.h
index 62498117c..e3a99b814 100644
--- a/kcmkwin/kwindecoration/kcm.h
+++ b/kcmkwin/kwindecoration/kcm.h
@@ -86,7 +86,6 @@ private Q_SLOTS:
 
 private:
     bool isSaveNeeded() const override;
-    bool isDefaults() const override;
 
     int borderSizeIndexFromString(const QString &size) const;
     QString borderSizeIndexToString(int index) const;